This is the first complete critical edition of ›The Port-Royal Logic‹. The first volume (Tome I) is a facsimile reprint of the rare first edition of 1662; in a strictly synoptically structured variant apparatus, the second volume (Tomes II/III) lists the manuscript variants (Fr. 19915 of Bibliothèque Nationale) for the first time as well as all the pertinent changes in the editions which were published during the authors‹ lifetimes. Furthermore, it provides analyses of the history of the text‹s development as well as a verification of all the quotations.